Optical disk recorders have often employed rotary lens holders in which the lens is axially moveable in the holder along the optical axis of the lens. Such motions enable focusing operations to occur using the objective lens. Further, the rotational mode of the lens holder enables the lens to be moved from a record track to an adjacent record track or a plurality of such record tracks by a track seek operation, as is known. Such a lens holder is usually located on a head carriage, also termed a coarse actuator in which an upstanding pin slidable and rotatably receives a lens holder. In optical disk recorders, because of extremely high track density and lineal recording densities, any tolerances between the upstanding pin and the lens holder may cause vibration and introduce an independent variable which has to be accommodated by servo circuits. In many instances, the wobbling or other action of the rotatable lens holder (also termed actuator) relative to the head or transducer carriage becomes significant at track spacings of about one micron and with a substantial linear density in which the cells are a micron or less in length along the track.
Physical orientation of the drive, hence the rotary actuator, can be either horizontal or vertical with either a right or left side being upward. It is desired to automatically ascertain the physical orientation for better controlling the rotary actuator. Once the physical orientation of the rotary actuator has been ascertained, then the control of the rotary actuator can be optimized. This determination of orientation and optimizing the control of a rotary actuator has particular utility in head arm positioning apparatus in which the rotary actuator is carried on a head arm carriage that linearly reciprocates radially of an data storing disk. Other applications may also advantageously employ the present invention.
Similar problems occur in other recorders such as so-called hard disk recorders in which the magnetic transducer is rotatably mounted for track crossings and for track seeking. As the track densities of such hard magnetic hard disks increase the sensitivity to the tolerances of the pivoting rotatable support becomes more and more critical. Accordingly, it is desired to provide a simple and efficient control of the relationship between a rotary actuator or transducer holder (also termed working tool holder) and its support whether it be on a head carriage or on a frame of a device that uses such a rotatable actuator. In particular, it is desired to calibrate the operation of the rotary actuator or working tool holder to accommodate different physical orientations of the rotary actuator.